National 28521 Manual Transmission Input Shaft Race

Overview of National 28521 Manual Transmission Input Shaft Race

The National 28521 manual transmission input shaft race is a precision-engineered taper bearing cup designed for reliable performance in various manual transmission systems. Compatible with multiple vehicle makes and models, this component ensures proper fit and function in demanding automotive applications.

• Cup Bore Diameter: 3.6250 inches (92.0750 mm)
• Cup Length: 0.7813 inches (19.8450 mm)
• Cup Radius: 0.0310 inches (0.7870 mm)
• Part Type: Taper bearing cup
• Part Number: 28521

Detailed Product Description and Specifications

The National 28521 input shaft race is manufactured to precise dimensions, including a cup bore of 3.6250 inches (92.0750 mm) and a cup length of 0.7813 inches (19.8450 mm). The taper bearing cup design supports smooth rotation and load distribution within the manual transmission assembly. The cup radius of 0.0310 inches (0.7870 mm) contributes to the proper seating and alignment of the bearing components, reducing wear and enhancing transmission longevity.

Compatible Vehicles and Applications

This manual transmission input shaft race is compatible with a range of vehicles, including Audi models like the R8, Bentley Continental and Flying Spur, Buick LeSabre and Century, Chevrolet Silverado 2500 HD and 3500, Ford F-100 through F-350 Super Duty series, GMC Sierra 2500 HD and 3500, Ferrari Testarossa, Lamborghini Gallardo, and Rolls-Royce Phantom. The part number 28521 is specifically designed to meet the fitment requirements of these models, ensuring proper installation and function.

Common Issues Addressed by the National 28521 Input Shaft Race

• Wear or damage to the existing taper bearing cup causing transmission noise
• Improper bearing alignment leading to premature transmission component failure
• Excessive play or looseness in the input shaft assembly
• Transmission input shaft bearing race corrosion or pitting
• Replacement during manual transmission rebuilds or maintenance

Installation Notes and Tips

• Ensure the transmission input shaft and housing are clean and free of debris before installation
• Use appropriate tools to press the taper bearing cup into place without damaging the cup bore or radius
• Verify correct orientation of the bearing cup according to vehicle service manual specifications
• Check for proper fit and clearance after installation to avoid premature wear
• Consult vehicle-specific repair guides for torque specifications and assembly procedures

Quality Assurance and Warranty Information

National manufactures the 28521 input shaft race to meet industry standards for durability and precision. Each part undergoes quality control inspections to ensure dimensional accuracy and material integrity. While specific warranty details may vary, National typically offers coverage against manufacturing defects to support professional repair and maintenance needs.